Process for synthesis of diamines



Patented May 26, 1953 UNITED STATES PATENT OFFICE 2,640,082

PROCESS FOR SYN THESIS F DIAMINES Ralph Ci :Schreyer, Wilmington, .DeL, assignor to E. I. du Pont de Nemours and Company, Wil .mington, Del., a. corporation of Delaware No Drawing. Application November 8, 1950, Serial No. 194,726

(Cl. Milk-.583

.1 Claim. 1

This invention relates to a new process 101' synthesizing diamines from relatively simple starting materials, and it also relates to certain new diamines which can be produced :by this process.

It is an object of this invention to provide a novel two-step process for synthesizing diamines Another object of the invention is to provide diamines capable of being produced in a most economical manner from relatively simple starting materials. Other objects of the invention -wi appear hereinafter.

In accordance with this invention is hasbeen discovered that diammes can be produced in a very practical manner by means of an entirely new route. The process involves thereaction of hexenenitriles of the formula:

tin-{Masses wherein the bonds shown may carry either hydrogen or alkyl groups containing not more than five carbon atoms, and, R is an alkyl group containing not more than live carbon atoms, with carbon monoxide and hydrogen in the presence of a hydrocarbonylation catalyst to produce 6- cyanoehexanals, which are in turn subjected to reductive .amination in the presence of'hydrogen, ammonia and a hydrogenation catalyst to produce substituted hepta'methylenediamines.

In accordance with apreferred embodiment of this invention, the starting'material employed in the foregoing two-step process is the adduct formed by reaction between an olefin :of the formula I R I has and: an unsaturated nitrile of 'the tormula According to another preferred embodiment of the invention, '5-methyl-5-hexenenitrile is reacted with carbon monoxide :andfhydrogen in the presence of a cobalt hydrocarbonylation catalyst to produce 6-cyano-3-methylhexana1, which in turn is subjected to reductive amination in the presence of ammonia, "hydrogen and a hydrogenation catalyst to produce the novel compound, d-methylheptamethylenediaminahaving the formula,

era

NELCIHE- CH2. EH. OH2)4.NHs

having aboiling..point.ol53-60 c. (0.4-0.6 mm.) and a refractive index N =lA601.

In carrying out the first ste of the present invention, the hexenenitrlle is reacted with at least 1 mol of carbon monoxide and 1 mol of hydrogen per mol of hexenenitrile. Preferably the carbon monoxide and hydrogen are employed in amounts considerably in excess of the stoichiometric requirements, the ratio of carbon monoxide to hydrogen being from about 2:1 to 1:3. The reaction may be carried out at temperatures of from C. to 200 C, and prefer ably from 150 C. to 175. Catalysts which are useful in carrying out this step include hydrogenation catalysts in general, as Well as the carbonyls and soluble salts of various hydrogenating metals. Cataiysts of this general nature are referred to as hydrocarbonylation catalysts. The preferred hydrocarbonylation catalysts comprise cobalt, which may be employed, for instance, in the metallic form, in the form of a soluble salt such .as cobalt naphthenate, in the form of insolublecompounds such as cobalt oxides, or in the form of cobalt carbonyls. Pressures of at least 5.0 atmospheres, and preferably in excess of 3,25 atmospheres, are employed in this step.

The reductive amination step is carried out in the presence of at least one mol of ammonia and at least 3 mols of hydrogen per mol of the 6- cyano-hexanal. Preferably large excesses of both hydrogen and ammonia are employed. Since the catalysts employed in the hydrocarbonylation step are for. the most part also useful in promoting the reductive amination step, it is often advantageous to employ as the starting material for this latter step the crude mixture resulting from the first step of the process. Alternately, the d-cyano-hexanol producedin the first step may be purified to the desired extent, as by distillation or the like, prior to the reductive amination step.

Either the same catalyst or a different catalyst may be employed in the reductive-elimination step. Catalysts which are useful .inthis-step includet-he hydrogenation catalysts generally; and in particular the cobalt-containing hydrogenation catalysts. The reductive amination step is carried out at temperatures of from 75 C. to 250 0., and preferably at temperatures of from C. to C. The pressure employed in this step should lie-greater than 50- atmospheres, and referably in excess of 300 atmospheres.

The startingmaterials employed in the process .of the invention are the 5-hexenenitriles of the formula '4 EXAMPLE3 Preparation of 3-neopentylheptamethylenediamine A mixture of 50 grams of 5-neopentyl-5-hexenenitrile, 100 cc; of dlethyl ther=and grams of reduced cobalt oxide catalyst was processed with a 1:1 gas mixture of carbon monoxide and a hydrogen at 172 C.-175 C. and 700 atmospheres as the adducts of an olefin such as isobutylene, 10 pressure for 1 110111 The resulting 6-cya 0- diisobutylene, propylene or amylene with an unneopentylhexanal was processed with about 102 saturated nitrile such as acrylonitrile or methgrams a m 58mins O reduced Cobalt acrylonitrile. When 5-methyl-5-hexenenitrile is ide catalyst and an excess of hydrogen at 160 employed as the starting material, the novel and C.-l85 C. and 700 atmospheres pressure for one important diamine, 3-methylheptamethylenedihour. Upondistillation of the product there was amine is obtained in a most practical and ecoobtained a good yield of the compound 3-neonomical manner. pentylheptamethylenediamine having a boiling The process of this invention and the novel point of 96 C.-98 C. (1 mm.), and a refractive diamines resulting from this process are illusindex N =1.4609. Analysis-calculated for trated by the following examples: C1aH2aN2! 'N, 14.00; neutral equivalent, 100. Found: N, 13.83; neutral equivalent, 100.7. 1

EXAMPLE 1 The hexenenitriles employed in the foregoing Preparation of 3 memymeptamethyzenediamine examples were obtained by the reaction of the suitable olefins and unsaturated nitriles at tem- A charge of 42.5 grams of 5-methyl-5-hexeneperatures of from 100 C.-300 C. and in mol nitrile, 150 cc. of diethyl ether, and 5 grams of a ratios of from about 1 to 4 mols olefin per mol of reduced cobalt oxide catalyst was processed with unsaturated nitrile. The 5-methyl-5-hexenea 1:1 gas mixture of carbon monoxide and hydronitrile employed in Example 1 was obtained as n t 150 C.175 C. and 700 atmosp eres pres the adduct of isobutylene and acrylonitrile. sure for 1.5 hours. The 6-cyano-3-methylhex- The starting materialfor Example2 was obtained anal thus obtained was subjected to reductive by reacting together methacrylonitrile andisoamination in the p e of about 119 grams of butylene. The 5-neopentyl-5-hexenenitrile emammonia, 5 grams of reduced cobalt oxide cataployed in Example 3 was obtained by processing lyst and an excess of hydrogen at 160 C.-170 C. 160 grams of diisobutylene, 53 grams of acryloand 700 atmospheres pressure for 1 hour. Disnitrile and 1 gram of hydroquinone at a temperatillation of the resulting reaction mixture gave a ture of 225 C. for 4 hours. In operating an over,- OOd yie d O t e novel Compound, 8t y1-hep all process for preparing diamines from unsatutamethylenediamihe, a ing a boiling point of rated nitriles, the olefiin-nitrile adduct, may, if 53 C.-60 C. (0.40.6 mm), and a refractive desired, be subjected to a purification treatment index N =1.4601. Analysiscalculated for prior to the hydrocarbonylation step. Cal-IzoNe: C, 66.5; H, 13.87; N, 19.45; neutral The process of this invention makes possible equivalent, 72. Found: C, 64.78; H, 13:65; N, the preparation of highly useful diamines in a 19.30; neutral equivalent, 73. simple manner from hexenenitriles, which, in turn, are readily obtainable from the reaction of EXAMPLE 2 low-molecular weight olefins and low-molecular Preparation of 2,5-dimethylheptamethylenedi- Weight unsaturated mtnlesamine The novel diamines produced by this process,

and in particular, 3-methylheptamethylenedlmixture of 30 grams of g 5'.. t -5- amine, have proved very valuable as intermedienenitrile, 150 cc. of diethyl ether and 5 grams of ates f the preparation 0i p l aml havin reduced cobalt oxide catalyst was processed with unusual p ope not obtainable 111 polyamldes a 1:1 gas mixtureof carbon monoxide and hydrop p f other diamine$- Properties of gen at 160 C.-170 C. and 700 atmospheres prestain of these polyamides are set forth in the folsure for 1 hour. The resulting 6-cyano-3,6-di- ,1 lowing table In this table. Yam Was methylhexanal was treated with 119 grams of ed f a polyamide produced from y ammonia, 10 grams of reduced cobalt oxide cataheptamethylenediamihe and terephthalic ac lyst and an excess of hydrogen at 165 C.-172 C. the original y av ng been elon ated 3. times and 700 atmospheres pressure for 1 hour. 'Distilby drawing at C. in order to pr t yarn lation of the product gave 15 grams of 2,5-diemployed in the tests. Yarn #2 was'derived from methylheptamethylenediamine, having a boiling 50 a polyamide produced from 3-neopentylheptapoint of'75 C.-78 C. (2.5-3 mm.) and a refracmethylenediamine and terephthalic acid, the tive index N =L459L Analysis--calculated for original yarn having been elongated 4.8- times by C9H22N2:N, 17.72; neutral equivalent, 79. Found: drawing at'l05' C. in order to produce the yarn N,- 17.59; neutral equivalent, 79. employed in the tests.

TABLE Zero Strength h Tensile Percent P v e i g Tem Mature, II. Strength, Elongation 1 ensle Quip-mice L. 0. vlscoslty grams/denier At Break gggr s Raw) 1% 3% 6% o 3$i::::::: lit sass $1; it it 81%? 8% 32 t l The compliance ratio is an arbitrary unit which is equal to load at 10% elongation 111111115 had at 5% elonuflm' The compliance ratio of wool is 1.0, While the compliance ratio of nylon is 0.

The high recovery properties and the high compliance ratio indicate that the polyamide derived from 3-methylheptamethylenediamine and terephthalic acid gives a yarn which may be highly useful in the manufacture of wool-like fabrics.

Since many modifications of the feature described herein can be made by those skilled in the art Without departing from the spirit and scope of the present invention, it is not intended that the invention should be restricted other than by the claim:

I claim:

A process which comprises reacting 5-methyl- 5-hexenenitrile with at least one mol of carbon monoxide and at least one mol of hydrogen per mol of the hexenenitrile at a temperature of 75 C. to 200 C. and at a pressure of at least 50 atmospheres in the presence of a catalyst taken from the group consisting of cobalt, cobalt naphthenate, cobalt oxides, and cobalt carbonyls to produce 6-cyano-3-methylhexanal, and thereafter reacting the 6-cyano-3 -methylhexanal thus produced with at least three mols of hydrogen and at least one mol of ammonia per mol of the hexanal at a temperature of 75 C. to 250 C. and at a pressure of at least atmospheres and separating 3-methy1heptamethylenediamine from the resulting reaction mixture.

RALPH C. SCI-IREYER.

References Cited in the file of this patent UNITED STATES PATENTS 

